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Biomedical subjects

M H Freeman

Publications and source records attributed to M H Freeman.

5 recordsLinked to original sources

Diffractive bifocal contact lenses in aphakia and pseudophakia. A pilot study.

Diffractive bifocal contact lenses function by diverting incident light to two focal points. Light from near objects is focused by diffraction while that from distant objects is focused by conventional refraction. Both processes occur simultaneously throughout the full aperture of the lens. Fourteen aphakic and pseudophakic contact lens wearers were fitted with diffractive bifocal lenses and observed for an eight week period. Six (42.8%) were satisfied with the visual result. Five subjects (35.7%) discontinued lens wear complaining of poor quality of near vision. We conclude that these lenses may help selected aphakic patients to discard their reading glasses but the low acceptance rate suggests that this type of optic is probably not suitable for implantation as an intraocular lens.

Accommodation, Ocular

Postoperative alterations in size of Dacron aortic grafts: an ultrasonic evaluation.

Reports of aneurysmal dilatation involving Dacron aortic prostheses have raised questions concerning the incidence, degree and significance of postoperative alterations in graft size. Consequently, a study was undertaken to evaluate Dacron graft size by ultrasooud in 95 asymptomatic patients selected at random after aortic surgery. A Vidison Real Time ultrasound unit was used to determine the internal diameter of the aortic portion of the various grafts utilized: 41 Cooley knitted, 25 Vasculour-D; 13 U.S.C.I. ultralightweight; nine Wesolowski Weavenit; and seven DeBakey standard weight knitted. Patients were studied at from two weeks to 138 months postoperatively (average of 33 months). Hypertension was present in 64% of patients. In the total series, the degree of mean dilatation was 17.6%. Average dilatation in patients with normotension was 15% compared to 21% in hypertensive patients. Graphic analysis of the data collected indicated that dilatation of a significant degree occurs in the immediate postoperative period and slowly increases with time; the time regression period and slowly increases with time; the time regression lines for normotensive and hypertensive patients were almost parallel. Results of this clinical study appear to corroborate the results of in vitro quality control tests performed by two graft manufacturers (Meadox and U.S.C.I.).

Aorta

Manifestations of hypertrophic pulmonary osteoarthropathy in patients with carcinoma of the lung. Demonstration by 99mTc-pyrophosphate bone scans.

Two patients with carcinoma of the lung were studied with 99mTc-stannous pyrophosphate. Resolution of scintigraphic activity was observed postoperatively in one patient, while the second patient showed an asymmetric pattern of radionuclide uptake and radiographic changes as well as clinical findings of hypertrophic pulmonary osteoarthropathy.

Aged

Focal splenic defects.

Review of more than 2,000 liver-spleen scans revealed 18 cases of focal splenic defects. Three major categories are defined: lymphoma, infarctions, and metastatic tumor. Clinical presentation is important in determining the precise etiology, and a differential diagnosis is presented. It appears that: (a) reticulum cell carcinoma is as likely to cause defects as is Hodgkin's disease; (b) splenic infarction is related to pancreatic disease through the splenic vein; and (c) malignant melanoma is the most common secondary deposit as detected by scanning.

Abscess